Floating roof seal construction



'R. s. EDENS' FLOATING ROOF SEAL CONSTRUCTION Aug. 20, 1957 2,803,371

Filed July 22, i954 Y g 'IIIIIIIII/(k IN V EN TOR.

United States hatent @flice Patented Aug. 20, 1957 FLOATING ROOF SEALCONSTRUCTIGN Robert S. Edens, Alhambra, Calif., assignor to SouthwestWelding & Mfg. Company, a corporation or" California Application July22, 1954, Serial No. 444,975

6 Claims. (Cl. 220-26) This invention relates to tanks for containingvolatile liquids such as gasoline or other volatile liquids. Such tanksare usually of large diameter and many of them are provided withfloating roofs usually of somewhat smaller diameter than the insidediameter of the tank. The tanks are practically always cylindrical inform, and are built of plate steel.

In order to prevent escape of volatile vapors from the contained liquid,it is the usual practice to provide means for sealing the annular spacebetween the side of the floating roof and the tank wall. As the liquidlevel in such a tank varies, problems are encountered in maintainingthis seal referred to, intact, and heretofore it has been the custom toemploy shoes of arcuate plate form that are held pressed against theinner face of the tank and connected with the floating roof, so thatthese shoes will rise and fall as the roof rises and falls with thechanges in the liquid level.

One of the objects of this invention is to provide simple means formaintaining the floating roof substantially centered on the axi of thetank, and for returning the same to true position in case it is moved tothe side by strong winds or by movements due to earthquakes, in casesuch tanks are in use in countries subject to earthquakes.

While it is necessary to impart any considerable rise or fall offloating roofs to the shoes, it i not essential to impart such movementson very slight up or down movements of the floating roof.

In other words, if there were a positive connection between a floatingroof and the shoes very slight up or down movement of the roof would beimparted to the shoes, and these movements would probably increase thewear and tear on the shoes and on the sealing flexible diaphragm that isgenerally employed to supplement the considerable sealing effect thatresults from the use of the shoes referred to, which are disposed withtheir side edges near together around the inner face of the wall of thetank.

Another object of this invention is to provide simple cans forestablishing a lost-motion connection between the shoes and the floatingroof which will enable the shoes to move with the roof when the roof isunder considerable movement, but which will absorb or dissipate shortmovements that are insignificant, but which would increase the wear onthe shoes if they were obliged to move with the roof at all times.

This invention particularly concerns the construction and use of loadedsprings mounted between the floating roof and the side of the tank formaintaining the roof in its centered position, and also for establishinga lost-motion between the roof and the shoes.

Another object of the invention is to provide connection from the roofto the shoes which will prevent their upper edges from moving radiallyoutwardly beyond the upper edge of the tank in case the roof rises to anunusually high level.

Further objects of the invention will appear from a careful reading ofthis specification and a study of the accompanying drawing.

The invention consists in the novel parts and combina- .tions of partsto be described hereinafter, all of which contribute to produce anefficient floating roof seal construction.

A preferred embodiment of the invention is described in the followingspecification, while the broad scope of the invention is pointed out inthe appended claims.

In the drawing:

Figure 1 is a vertical section taken on a substantially radial planefrom the axis. of the tank and taken adjacent to the location of one ofthe preloaded springs that keep the roof centered and also adjacent toone of the connections for causing the shoes to ride up or down with anyconsiderable movement of the floating roof as the liquid level changes.This view is a fragmentary view showing only a short portion of the tankwall in vertical section and showing only the edge portion of thefloating roof.

Figure 2 is a vertical section taken about on the line 22 of Figure 1,further illustrating the preferred detail of the mounting for one of thepreloaded springs.

Figure 3 is a vertical section taken about on the line 33 of Figure 1showing the detail of a preferred lostmotion connection. This view, likeFigure 2, is upon an enlarged scale.

Referring particularly to Figure l, 1 indicates a portion of the wall ofa cylindrical tank, such as is usually employed as a container for avolatile liquid.

In applying the invention to such a tank a plurality of shoes 2 areprovided that are disposed around the interior of the tank, and heldpressed against the wall thereof. These shoes are composed of anysuitable metal and are of arcuate form in horizontal sections on thesame radius as the inner surface of the tank wall so that they conformclosely to the same, thereby enabling them to function throughout theircross-sections as seals for preventing the vapors from the liquid in thetank from ascending past the floating roof 3.

These shoes are located rather close together at their side edges 4 atwhich gaps such as the gap 5 occur throughout the circumference of theroof. At the upper and lower edges the shoes are preferably bent toprovide them with curved arcuate tips 6.

in order to connect these shoes to the floating roof so as to enablethem to rise and fall with changes in the liquid level within the tank,which may be located at any point such as indicated by the line 7, Iprovide means preferably including one or more strut links 8correspending to each shoe. This connecting means preferably includes alost motion connection which functions in such a way that it will notimpart every small up and down movement of the roof to the shoes, but ifa considerable movement in either direction occurs, such a movement willbe imparted to the shoes. In order to accomplish this I prefer to mountthe strut links so that they are disposed in a vertical plane thatextends substantially radially from the axis of the roof and tank which,

course, substantially coincide with each other.

in providing this last named connection, it should be rider-stood thatit can be associated with these strut links in any way. In the presentinstance, the bodies 9 of the strut links may be formed of a length ofpipe, the upper end of which may be provided with a cross-T or sleeve itcarrying a through pin 11 the ends of which extend through a pair ofslots 12 which are formed in a vertical lane in two fins 13 of plateform that may be welded at their inner ends 14 to the inner face of theshoe.

At the lower end a connection 15 can be made which includes the use oftwo parallel fins 16 similar to the fins V i 3 I 13, with the exceptionthat in this case the slots are omitted, and each connection includes across pin 17 capable of oscillating slightly in eyes or openings 18fitting to the diameter of the cross pins. 7 Between the side Wall 19and the floating roof at each shoe I prefer to provide loaded springmeans that exerts yielding pressure in an outward direction against theinner 'face of the shoes to maintain them closely against the Wall ofthe tank. In addition to this function this means can be applied tomaintain the floating roof centered on the axis of the tank. In order toassure this, these springs should not have too liberal a tolerance .asregards the force they are capable of exerting against the shoes, sothat when the floating roof is in a center position all of the loadedsprings will be exerting substantially the same pressure upon the shoes.

In the present instance, the loaded springs I employ preferably consistof flat leaf springs 20 composed of a good quality of steel, and thesesprings are preferably .mounted on the roof as indicated in Figures 1and 2. It will be evident that each leaf spring has a relatively longbody 21, the upper portion of which is disposed in a substantiallystraight line inclining downwardly and outwardly toward the location ofthe shoes, and the lower .portion of each spring merges into the curvedor arcuate extension '22, the outer face of which maintains a conditionof tangency on the inner face of its corresponding ;shoe. At its upperend the body 21 of each spring is .bent toform a relatively short shank23, the tip of which is secured to the side wall of the roof 3 by beingbent in the form of a tube or eye 24 to receive a cross pin 25, .whichpin is supported between two fins 26 that may be welded to the outerface of the side wall 19 of the floating roof. In other words, at thejunction between the shank 23 and body 21a bend or knee 27 is formedwhich is pressed by the resiliency of the loaded spring against theouter face of the side wall 19 of the floating roof.

At the level of this knee 27, I prefer to locate the upper 28 isrelatively thin, and the floating roof of relatively 7 large diameter.

I prefer to employ at least two loaded springs to correspond to eachshoe. Of course, this would depend upon the width of the shoes, and intanks of relatively small diameter it might be possible to use only onespring if a ,relatively great number of shoes were employed; but forbest efliciency, at least two shoes are recommended, using jmore if thewidth of the shoes is unusually great.

In order to complete the sealing of the annular space or gap between theside wall of the floating roof and the side of the tank it is preferableto provide a continuous steel angle iron 30, the vertical web of whichmay be attached by welding as at 31 and 32 to the inner face of the sidewall 19. The flange 33 of this angle is punched to receive bolts 34 toattach a follower ring 35 to clamp down on the inner edge of an annularflexible diaphragm 36, composed of any suitable material made, ofcourse, impervious to the action of a volatile liquid that is containedin the tank.

In order to establish this very effective seal to the upper portions ofthe shoes I provide an inward offset 37 ex tending transversely on eachshoe and all the way across it. The bottom of this gutter or offset ispunched to 'receive clamping bolts 38 which clamp on a clamping '40 ofchannel form, also held in position by the nuts of 'the bolts, so thatthe edges of the flanges 41 are pressed against the surface of thediaphragm at each side of the channel or gutter 37.

All of the pins 11, 17, and 25 are provided with split pins 42 toprevent them from working loose.

Many other embodiments of this invention may be resorted to withoutdeparting from the spirit of the invention.

I claim as my invention and desire to secure by Letters Patent: 7 a a 1.In a seal hanger construction for a floating roof in a tank having asubstantially cylindrical upright wall, for containing a volatile liquidor the like, the combination of a floating roof within the tank, tofloat on the liquid, and to rise and fall with changes of the liquidlevel, a plurality of arcuate sheet metal shoes disposed around theinner face of the tank wall and conforming to the wall so as tocooperate with a flexible diaphragm to seal the tank against evaporationof liquid from the tank, means including at least two strut memberscorresponding to each of said shoes, each of said strut members beingindependent of any other, said strut-members extending in an inclineddirection upwardly and outwardly between the side of the correspondingshoe, a pivotal connection for the lower end of each strut memberincluding a pair of spaced brackets attached to the side of the roofwith a pivot pin carried there by and passing through the lower end ofthe strut member; a lost-motion connection at the upper end of eachstrut-member including a pair of spaced plates secured to the shoe,projecting toward the roof and having parallel slots extendingsubstantially vertically in the same, with a transverse pin carried bythe upper end of the strut member with its ends running in said slots,and permitting a limited up-and-down movement of the roof independentlyof the shoe, a plurality of leaf springs corresponding to said shoes,bracket means for each spring including two spaced plates projectingfrom the side of said roof with a pin attached to the same, each springhaving an eye at its upper end carried on its corresponding pin, saidspring having a shank extending toward the side of the roof with aknuckle connecting to the body of the spring and pressing forciblyagainst the side of the roof, said spring having a straight extensionfrom the shank with an arcuate extension with its convex side riding onand pressing by its own resilience and its cooperation with saidknuckle, to maintain the spring in a loaded state, all of said leafsprings cooperating to maintain the roof centered in the tank.

2. A seal hanger construction for a floating roof according to claim 2in which the said spaced slotted plates are welded at their outer edgesto the faces of the shoes.

3. A seal hanger construction for a floating roof according to claim 2in which the strut-member is of tubular form, and the said eye is ofsleeve form.

4. In a roof hanger construction for a circular floating roof floatableon a liquid in spaced relation to a vertical cylindrical wall of a tank,a flexible diaphragm sealing means sealing the space between thecircular roof and vertical cylindrical wall preventing the escape offluid therebetween, a plurality of circumferentially spaced arcuatehanger shoes slidably engaging the cylindrical wall of the tank, annularmeans connecting the diaphragm to the hanger shoes adjacent thecylindrical wall and for retaining the hanger shoes thereagainst, saidroof hanger construction including rigid means. providing a lost motionconnection between the floating roof and the hanger shoes and resilientmeans for centering the floating roof relative to the cylindrical wallof the tank, said rigid means including a plurality of unitary strutlink members, at least one strut-link member for each hanger shoe, saidstrut-link members lying in radial planes relative to the vertical axisof the floating roof and extending upwardly and outwardly therefrom,upper and lower support means for each strut-link member, said supportmeans supporting each strut-link member only at each respective end,each of said lower support means comprising a pivot means pivotallymounting the respective lower ends of the strut-link members to thefloating roof, each of the upper support means comprising a pin and slotconnection slidably mounting the respective upper end of the strut-linkmembers to the respective hanger shoes, whereby slight rising andfalling movement of the floating roof in relation to the verticalcylindrical wall of the tank may occur without sliding said hangershoes, said resilient means comprising a plurality of leaf springs, atleast one for each hanger shoe, for centering the floating roof and forpressing the hanger shoes against the cylindrical wall of the tank, eachof said leaf springs being pivoted at their upper ends on the floatingroot and being outwardly and downwardly included with respect to saidvertical axis, into contact with a lower portion or the respectivehanger shoe, each leaf spring having an inwardly bent knee below therespective pivotal onnection, said knee engaging the floating roof andloading the spring to exert yielding pressure against the lower portionof the respective hanger shoe.

5. In a seal hanger construction for a circular floating roof carried ona liquid in a tank having a cylindrical wall, said roof rising andfalling with the level of the liquid and having a plurality of hangershoes or" arcuate form to slide up and down on the inner face of thetank wall, the combination of a plurality of leaf springs disposedbetween the periphery of the roof and the side wall of the tank, each ofsaid springs having a substantially straight body portion extendingdownwardly and outwardly into engagement with a hanger shoe and eachspring having an integral shank at its upper end projecting upwardly andoutwardly at an angle so as to form a knee resting against the peripheryof the roof, and pivotal means securing the end of said shank to theperiphery of the roof, and the engagement of said knees with theperiphery of the roof placing said springs in a loaded state andmaintaining the roof centered in the tank; a plurality of singlestrut-link members disposed in pairs corresponding to each of thearcuate shoes, each of said strut-link members having a pivotedconnection to the periphery of the roof at their lower ends andextending upwardly and outwardly toward the shoes and each havinglost-motion connection respectively at the upper end thereof to theinner face of the respective shoe.

6. In a seal hanger construction for a floating roof in a tank having asubstantially cylindrical upright wall, for containing a volatile liquidor the like, and a circular floating roof within the tank spaced fromthe cylindrical wall, to float on the liquid, and to rise and fall withchanges of the liquid level, a plurality of arcuate hanger shoesdisposed around the inner face of the tank wall conforming to andslidably engaging the wall, an an- 6 nular flexible diaphragm having itsouter periphery connected to the hanger shoes and its inner peripheryconnected to the roof to seal the tank against evaporation of liquidtherefrom; the improvement comprising at least two unitary strut-linkmembers corresponding to each of said shoes, each of said strut-linkmembers being independent of any other, said strut-link members extend--ing in an inclined direction upwardly and outwardly be-- tween the roofand the corresponding hanger shoe, a pivotal connection for the lowerend of each strut mem ber including a pair of spaced brackets attachedto the: roof with a pivot pin carried thereby and passing through thelower end of the strut member; a lost motion connection between theupper end of each strut-member and the corresponding hanger shoeincluding a pair of spaced plates secured to the hanger shoe, projectingtoward the roof and having parallel slots extending substantiallyvertically therein, a transverse pin carried by the upper end of thestrut member having its ends running in said slots, and permitting alimited up-and-down movement of the roof independently of the hangershoe, a plurality of leaf springs, at least one for each of said hangershoes, bracket means for each spring including two spaced platesprojecting from the periphery of said roof, a pin attached to saidplates, each spring having an eye at its upper end carried on itscorresponding pin, said spring having a crank shank extending toward theperiphery of the roof with a knee connecting to the body of the springand pressing forcibly against the periphery of the roof, said springhaving a substantially straight portion extending downwardly andoutwardly from the shank with an arcuate portion at its lower end havingthe convex side thereof riding on and pressing against the correspondinghanger shoe, the pressure of the knee against the periphery of the roofmaintaining the spring in a loaded state, said springs maintaining theroof centered in the tank.

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